1. Technical Field
The present invention relates to an oscillation circuit, an oscillator, an electronic apparatus, and a moving object.
2. Related Art
An AT-cut quartz crystal resonator constituting a temperature compensated crystal oscillator (TCXO) has a frequency fluctuating while drawing a curve approximated by a cubic curve, with the vicinity of 25 degrees as an inflection point, due to a variation in ambient temperature. In addition, since an oscillation circuit constituting an oscillator, or the like has temperature characteristics, a frequency also fluctuates by the effects. In the TCXO, a voltage signal for compensating for the frequency fluctuation is generated by a temperature compensation circuit and is applied to a varicap diode provided in an oscillation circuit, and thus a frequency fluctuation with respect to changes in ambient temperature is suppressed, thereby realizing a high level of frequency accuracy.
As an example of such a TCXO, JP-A-2007-67967 discloses a configuration of a TCXO, using a semiconductor substrate, which includes an oscillation circuit, an output buffer circuit, and a temperature sensor circuit. In the configuration, the output buffer circuit and the temperature sensor circuit are disposed at corners on a diagonal line of the semiconductor substrate or corners on the same side.
In the TCXO as disclosed in JP-A-2007-67967, wirings (power supply wiring and ground wiring) for supplying power to the output circuit having one heat source and the oscillation circuit are generally communized. In addition, a wiring for supplying power is generally thicker than other wirings, that is, has low resistance. For this reason, heat generated from the output circuit having one heat source is transferred to another circuit through a wiring for supplying power, for example, the oscillation circuit, and thus there is the possibility of an output frequency fluctuating.